[PATCH net 2/2] vhost/vsock: don't allow half-closed socket in the host

Stefano Garzarella
2019-10-11T13:08:17Z

vmci_transport never allowed half-closed socket on the host side.
In order to provide the same behaviour, we changed the
vhost_transport_stream_has_data() to return 0 (no data available)
if the peer (guest) closed the connection.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
drivers/vhost/vsock.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 9f57736fe15e..754120aa4478 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -58,6 +58,21 @@ static u32 vhost_transport_get_local_cid(void)
return VHOST_VSOCK_DEFAULT_HOST_CID;
}

+static s64 vhost_transport_stream_has_data(struct vsock_sock *vsk)
+{
+ /* vmci_transport doesn't allow half-closed socket on the host side.
+ * recv() on the host side returns EOF when the guest closes a
+ * connection, also if some data is still in the receive queue.
+ *
+ * In order to provide the same behaviour, we always return 0
+ * (no data available) if the peer (guest) closed the connection.
+ */
+ if (vsk->peer_shutdown == SHUTDOWN_MASK)
+ return 0;
+
+ return virtio_transport_stream_has_data(vsk);
+}
+
/* Callers that dereference the return value must hold vhost_vsock_mutex or the
* RCU read lock.
*/
@@ -804,7 +819,7 @@ static struct virtio_transport vhost_transport = {

.stream_enqueue = virtio_transport_stream_enqueue,
.stream_dequeue = virtio_transport_stream_dequeue,
- .stream_has_data = virtio_transport_stream_has_data,
+ .stream_has_data = vhost_transport_stream_has_data,
.stream_has_space = virtio_transport_stream_has_space,
.stream_rcvhiwat = virtio_transport_stream_rcvhiwat,
.stream_is_active = virtio_transport_stream_is_active,
--
2.21.0